The Respiratory System Flashcards
What can the respiratory tract be anatomically divided into?
The upper and lower respiratory tract.
What does the upper respiratory tract do?
It conducts air through the nose, pharynx and larynx.
What is the function of the upper respiratory tract?
Air conditioning and conduction
ingested material conduction.
Describe the passage of air in the lower respiratory tract.
Air is conducted from the trachea to the left and right main bronchus, supplying each lung.
It passes through the Loeb Bronchi to the lobes to the segmental and subsegmental bronchi to the segments and subsegments respectively.
It then passes through the terminal bronchioles to the respiratory bronchioles, alveola ducts and alveoli.
State the functions of the lower respiratory tract.
Air conduction and respiratory gas exchange.
What zones can the tracheobronchial tree be divided up into?
- the conducting airway zone
- the respiratory zone
- the transitional zone linking conducting and respiratory zones
Describe the conducting zone.
passageway for air - extends from the trachea to the end of the terminal bronchioles.
No gas exchange occurs
Walls are relatively thick, straight and smooth compared to respiratory zone airways allowing rapid airflow with minimal resistance.
Describe the respiratory zone.
Located in the respiratory bronchioles, alveolar ducts and alveoli.
Exchange of the respiratory gases (oxygen and carbon dioxide) occurs.
Describe the transition zone.
Links the terminal bronchioles with the alveolar ducts in the form of the respiratory bronchioles.
Air conduction gives way to gas exchange in the respiratory zone.
What does the respiratory zone consist of?
Part of the alveolar ducts and alveolar sacs (which contain groups of alveoli in a cluster-of-grapes-like arrangement).
Describe alveolar ducts and alveolar sacs.
thin epithelium and large surface area - enables rapid diffusion of respiratory gases during gaseous exchange.
Alveolar ducts have pouches in their walls for gas exchange which eventually give way to established dense clusters of alveoli.
What is meant by the term airway branching?
The trachea bifurcates (branches) to form the right and left main bronchus. The airways continue to branch in a dichotomous fashion until reaching the alveolar ducts.
What are airway generations?
airway branching points
How many airway generations are there in humans?
23
Describe airway generations in humans.
The trachea represents generation 0 and the main bronchi generation 1. Branching continues, with the airways becoming ever-smaller.
The terminal bronchioles are found at generation 8 and the transitional zone occurs at generation 15 - 16 with the alveoli marking generation 23 - the end of the tracheobronchial tree.
What type of epithelium cells line the nose?
Pseudostratified ciliated columnar epithelium
AKA: respiratory epithelium
Describe the function of Pseudostratified ciliated columnar epithelium in the nose
Integral to the respiratory defence mechanism
Role in warming, humidifying and filtering inspired air (known as air conditioning).
In the nose, what are the turbinates (conchae)?
3 ridges of tissue that project from the walls of each nasal cavity creating 3 main passages (the meatuses)
What are the turbinates of the nose responsible for?
help to increase the surface area exposed to inspired air
How do the meatuses condition inspired air?
Slow the flow: increased resistance to airflow the turbinates offer
Warm air: highly vascular nature of the respiratory epithelium lining the turbinates and adjacent nasal septum
Humidify air: moisture is released from the highly vascular respiratory epithelium lining the turbinates. This cools the epithelium so when warm expired air flows over it causes condensation and thus further humidification
What is the nasal vestibule also known as
the nostril
Describe the structure of the nasal vestibule
a cartilaginous opening to the nasal cavity
lined with squamous epithelium which has large hair projections called vibrissae.
describe the role of vibrissae in the nasal vestibule
help to filter the inspired air removing large particles, e.g. dust, to prevent entry to lower airways. This is part of the respiratory defence mechanism.
name the 3 main anatomical areas of the pharynx
nasopharynx
oropharynx
laryngopharynx
where is the nasopharynx?
extends from the base of the skull to the soft palate
what is the main role of the nasopharynx?
acts as an air conduction passageway from the nasal cavity to the oropharynx.
describe the structure of the nasopharynx and how it relates to its function
lined with pseudostratified ciliated columnar epithelium and therefore aids air conditioning, lung defence and mucociliary clearance.
describe the structure of the soft palate and how this relates to its function
comprised of muscle and connective tissue, and forms part of the roof of the mouth
elevates during swallowing to separate the oral cavity and nasopharynx thus helping prevent ingested materials entering the respiratory areas.
where is the oropharynx?
extends from the hard palate above to the upper border of the epiglottis below
what is the main function of the oropharynx
provides a common passageway for ingested material and air
describe the structure of the oropharynx and how this relates to its function
It has a stratified squamous epithelium (rather than a respiratory epithelium) to cope with repeated abrasion from ingested food/drink.
describe and name the structures present in the oropharynx.
The 2 palentine tonsils
formed from lymphoid tissue
act as part of the immune system.
what is stimulated when you touch the oropharynx and why?
The pharyngeal/gag reflex - acts as a further defence preventing foreign bodies from entering the laryngopharynx, larynx and lower respiratory tract.
where is the laryngopharynx?
extends from the epiglottis above to the cricoid cartilage of the larynx below